1. Field of the Invention
The present invention relates to a multilayer capacitor used as a noise filter or the like capable of reducing structural defects or the like to enhance reliability and reducing equivalent series inductance (ESL) to allow more effective execution of a noise countermeasure in a high frequency range, and more particularly, to that suitable for use in a circuit of data processing equipment and communication equipment.
2. Description of the Related Art
Data processing equipment and communication equipment in recent years are mostly digitalized, and further, the frequency of digital signals handled in these kinds of equipment is becoming higher in accordance with the increased speed of data processing capability. Accordingly, noises generated from these equipments similarly tend to increase in a high-frequency range. As a noise countermeasure, many of these equipments use electronic components for preventing electromagnetic interference and inhibiting unnecessary voltage fluctuation. Multilayer capacitors are in general use as such electronic components for noise countermeasure.
However, ESL (equivalent series inductance) which is a parasitic component of a multilayer capacitor acts as an obstruction to an effect of filtering out noises in a high-frequency range, and thus this effect is becoming less sufficient as the operating frequency or the like of the equipment is becoming still higher. In other words, multilayer capacitors having a large ESL such as a conventional one cannot respond to the recent tendency toward a higher frequency.
Therefore, in order to realize a noise countermeasure in a high-frequency range, multilayer feedthrough capacitors, which are multilayered type feedthrough capacitors, are manufactured for use as capacitors with reduced ESL. A multilayer feedthrough capacitor 110, which is shown in FIG. 6, FIG. 7(A), and FIG. 7(B), will be hereinafter described.
The multilayer feedthrough capacitor 110 has a multilayer body 120 shown in FIG. 6 in which dielectric sheets 122 and dielectric sheets 124 are stacked, the dielectric sheets 122 each having a first internal conductor 112 led out to two side faces opposite to each other, and the dielectric sheets 124 each having a second internal conductor 114 led out to two sides different from the abovementioned two sides, as shown in FIG. 7.
Further, a pair of terminal electrodes 132 both connected to the first internal conductors 112 are disposed on both ends of the multilayer body 120, and a pair of terminal electrodes 134 both connected to the second internal conductors 114 are disposed on both side faces of the multilayer body 120. The pair of terminal electrodes 132 are connectable to a signal line side and the pair of terminal electrodes 134 are connectable to a ground side.
However, since the frequency handled in recent equipment has become remarkably high, which further increases noises, and the lower power consumption of the equipment lowers operating voltage, noise resistance of the equipment is deteriorating. Under such circumstances, there is a demand for an electronic component for noise countermeasure exhibiting a high noise filtering effect in a higher frequency range. Moreover, further reduction in ESL is an important issue also for a multilayer feedthrough capacitor in order to cope with such a current situation.
Therefore, further reduction in ESL has been contemplated in the multilayer feedthrough capacitor as structured above. A design generally adopted for this purpose is such that, as shown in FIG. 8, the width dimension of leadout portions 114A of the second internal conductor 114 connected to the terminal electrodes 134 connected to the ground side are made as wide as possible and accordingly, the terminal electrodes 134 are also made wide.
However, when the width dimension of the leadout portions of the second internal conductor is increased, the joining strength between dielectrics is lowered at these portions. As a result, structural defects such as a crack may occur in these portions or the element strength of the multilayer body may be significantly lowered at the time of ceramic sintering for processing the dielectrics to the multilayer body. Accordingly, resistance against an external stress such as the deflection of a substrate deteriorates, giving rise to the concern about reliability deterioration.